The present invention relates to cycolor type color video printers for printing a color image by using a cycolor paper comprising a cylith film and a receiver paper, and more particularly to a roller type developing apparatus for said cycolor type color video printers.
Conventionally, a cycolor type color video printer is known as a system for printing a color image on a receiver paper by using a cylith film, which cylith film is applied with a great amount of cylith capsules thereon.
Referring to FIG. 1, a general cycolor type color video print (hereinafter, referred to simply as "a video printer") comprises a supply reel 11 for supplying the cylith film 9, a guide roller 12 for guiding the movement of said cylith film 9, a fiber optics cathode ray tube 13 (hereinafter, referred to simply as "a F/O CRT"), a capstan roller 14 and a pinch roller 15 each for guiding the cylith film 9, the developing apparatus 1 including upper and lower pressing rollers 23 and 24 and adapted for developing the color image on the receiver paper 10 by using said cylith film 9, a take-up reel 16 for taking up said cylith film 9 after the developing process is carried out by the developing apparatus, and a heater 17 for heating the receiver paper 10 having been transcribed with the color image so as to fix said color image. Therefore, the video printer carries out its printing operation by transcribing the color image from the cylith film 9 onto the receiver paper 10 by the developing apparatus 1 and fixing said transcribed color image, that is the developed color image on said receiver paper 10, by the heater 17.
On the other hand, the cylith film 9 generally comprises a laminated film substrate 9' and the great amount of cylith capsules 9" applied to said film substrate 9' as shown in FIGS. 1A and 1C, said capsules 9' photosensitive to respective R, G and B color lights. The cylith film 9 supplied from the supply reel 11 is exposed to the desired color image light by the F/O CRT 13, and then passes, together with the receiver paper 10 lying upon said exposed cylith film 9, between the upper and lower pressing rollers 23 and 24 of the developing apparatus 1. The upper and lower rollers 23 and 24 allow the cylith film 9 and the receiver paper 10 to pass therethrough with an optimal pressure so that the cylith capsules 9" are broken by means of the pressure, thereby transcribing the exposed color image of said cylith film 9 onto said receiver paper 10.
Generally, the cylith film 9 together with the receiver paper 10 are known as "a cycolor paper", and the transcribing process in which each cylith capsule 9" is broken by means of the pressure provided by the developing apparatus in order to transcribed the color image onto the receiver paper 10 is known as "developing process".
As shown in FIG. 1C, each cylith capsule 9" is formed as a fine grain comprising dyes 4 and a thermohardening photosensitive covering 5 containing said dyes 4 therein. The cylith capsule 9" has an unusual sensibility for R, G and B color lights and a diameter ranging from about 2 .mu.m to about 12 .mu.m. Upon being exposed to the color light, the photosensitive covering 5 of the cylith capsule 9" is cured in response to the intensity of said light.
The operation of the video printer for printing by using the cylith film 9 and the receiver paper 10 will be described in conjunction with FIGS. 1, 3A, 3B and 3C.
As shown in FIG. 3A which represents the exposing process for the cylith film 9, the cylith film 9 supplied from the supply reel 11 is exposed to the color light of the F/O CRT 13 provided with R, G and B fluorescent sources 6, 7 and 8 so that the photosensitive coverings 5 of respective cylith capsules 9" are cured in response to the R, G and B color lights.
The cyclith film 9 together with the receiver paper 10 then pass at an optimal pressure between the upper and lower pressing rollers 23 and 24 of the developing apparatus 1, as shown in FIG. 3B showing the developing process. At this time, the exposed photosensitive covering 5 of each cylith capsule 9" is broken so that the desired color image of the cylith film 9 is transcribed onto the receiver paper 10 by the transcription of the dyes 4 of said capsule 9" onto the receiver paper 10.
Thereafter, the cylith film 9 is took up by the take-up reel 16, while the receiver paper 10 having the color image thereon is heated by the heater 17 in order to fix said color image thereon.
The present invention especially relates to the developing apparatus 1 of the video printer, as above mentioned. An example of the known developing apparatus 1 is shown in FIGS. 4A and 4B which are a side view and an elevational sectional view of said known developing apparatus 1, respectively.
As shown in the drawings, the known developing apparatus 1 comprises a pair of said plates 21 and 21' mounted on the printer base 20 by means of setting screws 22 and 22' and spaced apart from each other, and a pair of pressing rollers 23 and 24 each rotatably disposed between the side plates 21 and 21'. The side plates 21 and 21' each is provided with a vertical mounting hole 21a, 21'a provided for receiving a pair of bearings 25 and 26 of the upper and lower pressing rollers 23 and 24, said bearings 25 and 26 located in order to contact with each other. Each of the upper and lower pressing rollers 23, 24 includes a pair of supporting shafts 23a, 23b integrally formed at both ends thereof and each having a smaller diameter than that of the pressing roller, said supporting shafts 23a and 24a each fixed to each bearing 25, 26. Each of said plates 21, 21' also includes lower and upper pressing plates 27 and 29, 27' and 29, and compression coil springs 28, 28' interposed between said upper and lower plates 27 and 29, 27' and 29, said lower pressing plate 27, 27' contacted to the upper bearing 25 of the upper pressing roller 23 at its under surface. An upper plate 30, 30' is fixed to each side plate 21, 21' and provided with an inner threaded hole 30a, 30'a at the center portion thereof, each said inner threaded hole 30a, 30'a receiving a pressure controlling bolt 32, 32'. Each of the pressure controlling bolt 32, 32' is contacted to the upper surface of the pressing plates 29, 29' at its lowermost end. Thus, each of the pressure controlling bolt 32, 32' biases said upper pressing plates 29, 29' downwards by being tightened as demanded.
Therefore upon tightening the pressure controlling bolts 32, 32', said bolts 32, 32' move downwards simultaneously with biasing the upper pressing plates 29, 29' downwards, thereby causing the compression coil springs 28, 28' to be compressed and the pressing power of the pressure controlling bolts 32, 32' to be transmitted to the upper support bearing 25 of the upper pressing roller 23. Thus, a desired pressure is provided for the upper and lower pressing rollers 23 and 24 so that the pressure necessary for the developing process of said developing apparatus can be controlled.
However, the known developing apparatus 1 has several disadvantages in that it needs to include the lower and upper pressing plates 27, 27', 29 and 29' and compression coil springs 29 and 29' for supporting the upper and lower pressing rollers 23 and 24, so that the height of the apparatus 1 is relatively higer, thereby causing the installing work for the video printer to be relatively difficult and the size of the video printer to be complex and enlarged. Also, because the upper and lower pressing rollers 23 and 24 usually contact with each other, the known developing apparatus 1 has another disadvantages in that there may be a danger of frictional damage on each outer contacting surface of the upper and lower pressing rollers 23 and 24, and a necessity of an auxiliary device for providing as demanded a clearance between said upper and lower pressing rollers 23 and 24 and maintaining said clearance without any displacement.
Furthermore, the known developing apparatus has still another disadvantage in that there may be as shown in FIG. 5 a deflection in the upper and lower pressing rollers 23 and 24 as the supporting shafts 23a and 24a thereof are pressed downwardly in order to provide an optimal pressure for said upper and lower pressing rollers 23 and 24, said pressure enough for breaking the cylith capsules 9" of the cylith film 9, by means of the pressure controlling bolts 32 and 32', thereby causing the jamming of the cycolor paper P and the bad printing result such as an unequal coloring result to occur.